Many filter type assemblies have been proposed for filtering out undesirable substances such as harmful tars which are carried by the smoke from the burning tobacco to the mouth of the inhaler. Various patents have disclosed the use of tubular filter assemblies which contain cross partitions, at right angles to the exterior wall of the tube which are perforated or slotted and have filter material in the chambers formed by the cross partitions to reduce the flow of harmful tars, etc. In U.S. Pat. No. 3,079,926 to Litchfield, et al, of Mar. 5, 1963 a series of circular baffles are slotted so that the smoke can pass through each chamber. A similar series of spaced apart, circular, disc partitions, each partition having perforations staggered in relation to each other, is disclosed in U.S. Pat. No. 3,167,076 to Mare of Jan. 26, 1965.
Cup shaped partitions, or truncated conical partitions, with staggered perforations, are proposed in U.S. Pat. No. 2,764,513 to Brothers of Sept. 25, 1956 and in U.S. Pat. No. 3,759,270 to Wright of Sept. 18, 1973.